(1) Field of the Invention
This invention relates to vibration isolation mounts having spring means for damping vibration of a body, and is directed more particularly to such a mount having means for locking the spring means in place during transitional periods of high vibrational activity or force loading.
(2) Description of the Prior Art
Vibration isolation mounts prevent unwanted vibrational forces from propagating from a device, such as a motor, into the environment, or to protect a device from its surroundings, as in seismic instrumentation isolation. The mount design and material properties are selected to achieve the desired degree of isolation, or damping, during normal operation.
A spring means is an inherent part of a vibration isolation mount. Vibrations exert an oscillating force on the spring means which "gives". During transient high-load events, as for example, in the start up of electric motors, or launch of a vehicle, the vibration mount may be subjected to conditions beyond its design limits. The spring means, which may be a viscoelastic material, such as rubber, may rupture or distort, permitting the protected device to move beyond safe limits.
Accordingly, there is a need for a vibration isolation mount having the usual flexibility during normal periods of operation of the protected device, but having means for automatically locking the spring means so as to prevent movement of the protected device beyond safe limits during unusually active vibrational activity of the device and/or during the occurrence of transient static loads on the device.